Answer:
Therefore the work done is 640 ft pound.
Step-by-step explanation:
Given that, a heavy rope 40 ft long, weighs 0.8 lb/ft.
Force = weight.
Let we pull x ft. Then the remain rope = (40-x)ft.
(40-x) ft it is variable.
The weight of (40-x) ft is =(40-x)0.8 lb
∴ Force =(40-x)0.8 lb
Work done = Force × displacement
= (40-x)0.8 Δx [ displacement = Δx]
Therefore ΔW =(40-x)0.8 Δx
Since total rope is pulling up on the top of the building. Total displacement = 40 ft.
Total work done 
![=[32x-\frac{0.8x^2}{2}]_0^{40}](https://tex.z-dn.net/?f=%3D%5B32x-%5Cfrac%7B0.8x%5E2%7D%7B2%7D%5D_0%5E%7B40%7D)
![=[(32\times 40)-0.4(40)^2]](https://tex.z-dn.net/?f=%3D%5B%2832%5Ctimes%2040%29-0.4%2840%29%5E2%5D)
=640 ft pound.
Therefore the work done is 640 ft pound.
The correct answer is
y=x²+2x+7
y=x+7
==>x²+2x+7=x+7
==>x²+x=0
==>x(x+1)=0
==>(x=0 and y=7) or (x=-1 and y=-1+7=6)
Sol={(0,7),(-1,6)}
Hope this helps!
Answer:
Step-by-step explanation:
4-2<x<4+2
2<x<6
x = 3, 4 or 5
i assume u r talking about triangle
Answer:
(-1, 1)
Step-by-step explanation:
Multiply f(x) or y value by -2, so (-1, 2) -> (-1, -4)
Add 5 to the f(x) or y value since it is a vertical translation, so (-1, -4) -> (-1, 1)
Answer:4A^2+9B^2
Step-by-step explanation: